In Brief: What happens when a man takes testosterone?
Several studies have shown that testosterone administration increases lean body mass, muscle strength, reduces waist circumference, improves glycemic control, lipid parameters, and thereby the overall quality of life. The effect of testosterone supplementation on the improvement of psychological and sexual parameters occurs rather rapidly.
Men with low levels of testosterone experience lack of sex drive, erectile dysfunction, depression, low energy levels, emotional distance, and insomnia.[2]
Testosterone replacement therapy in the form of injections, pills, patches, or gels is used to improve the symptoms of low testosterone.
Men also take testosterone- boosting supplements to improve their libido or build body mass.
Several studies showed that testosterone administration has a beneficial impact on body composition, psychological variables, and glucose homeostasis.
A study involving 43 regular athletes showed that testosterone supplementation increased strength in bench-press, muscle size, and squatting exercises.[3]
The testosterone administration was associated with a dose-dependent increase in skeletal muscle mass, leg strength, and power observed after 20 weeks.[4]
A study showed that 12 weeks long-acting testosterone administration improved exercise capacity, muscle strength, glucose metabolism in men with moderately severe chronic heart failure.[5]
Supplemental testosterone during rigorous exercise and diet-induced energy deficit does not appear to attenuate the lower-body functional decline.[6]
Testosterone supplementation in older men after three months showed an increase in lean body mass, a decline in total cholesterol, and low-density lipoprotein.[7]
It did not, however, affect the functional status or cognition and had mixed metabolic effects[8].
In a study involving 117 men aged 34-69 years, supplementation of testosterone undecanoate for one year showed improvement in body weight, BMI, and waist size.[9]
Oral treatment of testosterone improved glucose homeostasis in type II diabetic men.[10]
A systematic review of randomized controlled trials showed that intramuscular testosterone increased lumbar bone density in androgen-deficit men.[11]
Lower levels of testosterone may impact the quality of life. A study showed that sexual function and mood changed after 30 days of testosterone administration in hypogonadal men.[12]
In addition to the improvement of sexual functions, testosterone supplementation may improve bladder functions and compliance in men with symptomatic late-onset hypogonadism.[13]
Another study showed that testosterone decreased depression scores after six weeks, improved concentration after three weeks, self-confidence between 3-6 weeks, and reduced fatigue after 9-12 weeks.[14]
Although several studies reported the positive effects of testosterone supplementation, long term risks, safety, and efficacy, especially in older men, are not known.
Evidence-based, long-term, randomized clinical trials are required in the future.
Therefore, it is recommended to consult a medical practitioner before taking testosterone for underlying risks.